In recent years, liquid crystal displays are often used as flat panel displays in various fields. However, contrast and shade greatly vary depending on viewing angles. A need for a light source such as a backlight hinders lower power consumption. Reduction in the thickness and weight of a liquid crystal display is limited. These serious problems still remain. Liquid crystal displays have serious problems also in flexibility.
To address the problems, self-luminous organic EL displays including organic EL elements are expected in place of liquid crystal displays. In an organic EL element, a current flows through organic EL layers sandwiched between an anode and a cathode so that organic molecules forming the organic EL layers emit light. Organic EL displays including such an organic EL element, which are self-luminous, have their thickness and weight easily reduced, and consume less power. The organic EL displays, which have a wide viewing angle, receive great attention as flat panels that have an advantage over liquid crystal panels.
Organic EL displays including a plastic substrate draw special attention. The plastic substrate has higher flexibility, higher shock resistance, and lower weight than a glass substrate. Such a plastic substrate would provide new organic EL displays beyond typical displays including a glass substrate.
However, in general, after a certain period of drive, light-emitting characteristics, such as brightness and uniformity in light emission, of an organic EL clement deteriorate significantly from the initial state. The deterioration in the light-emitting characteristics attributes to deterioration of an organic layer due to moisture of outside air, which has entered the organic EL element, or separation of the organic layer from an electrode due to moisture.
To address the problems, a technique in which a sealing film is provided to reduce entry of gas generated by moisture is disclosed. More specifically, for example, an organic EL display including a flexible plastic substrate (a film substrate) and a sealing film is disclosed. The sealing film is provided on the plastic substrate, and includes a stress relief layer and an inorganic layer, which are stacked one over the other. Such a configuration may reduce the deterioration of the organic EL display due to moisture and gas, and may improve the reliability of the organic EL display (see, for example, Patent Document 1).